Method and system for transmitting information via the radio interface between a subscriber equipment and a network equipment of a cellular mobile radiotelephone network

Abstract

The renew characters (R1/R2 or, respectively, R1'/R2') that are entered into a transmission frame by the subscriber equipment (MS) or by the network equipment (IWF) upon setup or resetting of the information protection connection indicate a frame number of a frame that has not yet been sent or, respectively, of a frame that is guaranteed to have been received. The first numbered transmission frame (NFR) to be sent in the information transmission phase after the setup or resetting receives the frame number. As a result of the renew character, the same static starting value is not always employed for the numbering of the frames to be sent after the setup or resetting of the information protection connection. It can thus be reliably recognized whether the frame was sent before or after the setup or, respectively, resetting of the information protection connection. Despite different delays on the transmission paths that, for example, can effect a mutual overtaking of individual frames, the renew characters guarantee that an undetected information loss or, respectively, an undetected information generation does not occur at the receiver of the numbered frames. The receiver can reliably recognize the validity of the frames.

What is claimed is: 
     
       1. A method for transmitting information via a radio interface between subscriber equipment and network equipment of a cellular mobile radiotelephone network, comprising the steps of: transmitting information to the radio interface by a radio link and protecting the information with a protection protocol;   setting up or resetting of an information protection connection by the subscriber equipment or by the network equipment in order to subsequently successively transmit transmission frames, each of the frames having a header field and an information field;   providing at least one renew character, which provides the first numbered transmission frame to be sent with a frame number that is a function of the at least one renew character, is respectively entered into the header field of a transmission frame for respectively initiating or acknowledging the setup or resetting of the information protection connection, said frame number belonging to a numbered transmission frame that was not yet sent or that is sure to have reached the subscriber equipment or the network equipment before initiation or acknowledgment of the setting up or resetting.   
     
     
       2. The method according to claim 1, wherein a transmission variable, which determines the frame number of the next numbered transmission frame to be sent in the sequence, is set with reference to the renew characters to a starting value for numbering of frames to be sent. 
     
     
       3. The method according to claim 1, wherein a transmission variable, which determines the frame number of the next numbered transmission frame to be sent in the sequence, is set with reference to the renew characters to a starting value for numbering of frames to be sent that is composed of the renew characters themselves. 
     
     
       4. The method according to claim 1, wherein a reception variable, which determines the frame number of the next numbered transmission frame to be received in the sequence, is set with reference to the renew characters to a starting value for numbering of arriving frames. 
     
     
       5. The method according to claim 1, wherein a reception variable, which determines a frame number of a next numbered transmission frame to be received in a sequence, is set with reference to the renew characters to a starting value for numbering of arriving frames is composed of the renew characters themselves. 
     
     
       6. The method according to claim 1, wherein the renew characters are respectively sent by the subscriber equipment or by the network equipment in the transmission frame together with a message with which the setup or the resetting of the information protection connection is initiated or are sent back together with an answer message which acknowledges an entry into the information transmission phase. 
     
     
       7. A system for transmitting information via a radio interface between subscriber equipment and network equipment of a cellular mobile radiotelephone network using a protection protocol for protecting the information transmitted to the radio interface via a radio link, comprising: each of the subscriber equipment and the network equipment having a system for setting up or for resetting of an information protection connection in order to subsequently successively transmit transmission frames, each of the frames having a header field and an information field, in an information transmission phase;   at least one renew character, which provides a first numbered transmission frame to be sent with a frame number allocated thereto that is a function of the at least one renew character, the character being respectively entered into the header field of a transmission frame for respectively initiating or acknowledging the setup or resetting of the information protection connection, said frame number belonging to a numbered transmission frame that was not yet sent or that is sure to have reached the subscriber equipment or the network equipment before initiation or acknowledgment of the setting up or resetting.   
     
     
       8. Subscriber equipment for transmitting or, respectively, receiving information via a radio interface to or, respectively, from network equipment of a cellular mobile radiotelephone network using a protection protocol for protecting the information transmitted to the radio interface via a radio link, comprising: system for setting up or for resetting of an information protection connection in order to subsequently successively transmit transmission frames that is a function of the at east one renew character, each of the frames having a header field and an information field, in an information transmission phase;   system in the subscriber equipment for entering at least one renew character, which provides the first numbered transmission frame to be sent with a frame number allocated thereto, into the header field of a transmission frame for respectively initiating and acknowledging the setup or resetting of the information protection connection, said frame number belonging to a numbered transmission frame that was not yet sent or that is sure to have reached the subscriber equipment or the network equipment before initiation or acknowledgment of the setting up or resetting.   
     
     
       9. Network equipment of a cellular mobile radiotelephone network for transmitting or, respectively, receiving information via a radio interface to or, respectively, from subscriber equipment using a protection protocol for protecting the information transmitted to the radio interface via a radio link, comprising: system for setting up or for resetting of an information protection connection in order to subsequently successively transmit transmission frames, each of the frames having a header field and an information field, in an information transmission phase;   system in the network equipment for entering at least one renew character, which provides the first numbered transmission frame to be sent with a frame number allocated thereto that is a function of the at least one renew character, into the header field of a transmission frame for respectively initiating and acknowledging the setup or resetting of the information protection connection, said frame number belonging to a numbered transmission frame that was not yet sent or that is sure to have reached the subscriber equipment or the network equipment before initiation or acknowledgment of the setting up or resetting.